1. Field of the Invention
The present invention relates to a side-view type light emitting device, and more particularly, to a side-view type light emitting device having a structure capable of providing uniform light irradiation on a test target such as a light guide panel (LGP) and an optical device including the side-view type light emitting device.
2. Description of the Related Art
In general, a light emitting diode (LED) is provided as a light emitting device that has a package body with a lead frame connected to an electrode. The light emitting diode is widely used in various application fields, in combination with a variety of light receiving devices such as a backlight unit of a liquid crystal display, a light guide panel of a surface emitting display, and an optical sensor.
Specifically, a side-view type light emitting device (a kind of light emitting device) is widely used as a light source for a backlight unit of a liquid crystal display.
The backlight unit must maintain the light uniformity throughout the entire panel in spite of the trend toward the wide area thereof. However, because an LED light source used as a light source for the backlight unit is a point light source, it has a limitation in the light uniformity in comparison with a conventional CCFL that is a line light source. Also, because the number of LEDs mounted on a circuit board increases with an increase in the BLU area, the positional accuracy of the mounted LEDs must also be secured. However, the tolerance of a reflow soldering process, which is generally used as a mounting process, causes a variation in the position of the LED on an FPCB. Also, a distance change of the light guide panel and the backlight unit and the LED may occur in alignment with the backlight unit.
A method of mounting a light emitting device closely on a light input surface of a light guide panel is used to prevent the above problems. However, when the light guide panel is expanded by the heat generated during the operation of an LED, the distance between the LED and the light guide panel changes or they are closely adhered to each other, thus making it difficult to provide uniform light irradiation.